Election Commissioner SY Qureshi today strongly defended the use of Electronic Voting Machines (EVMs), saying they were tamperproof and had passed all tests over the years.

Election Commissioner SY Qureshi on Wednesday strongly defended the use of Electronic Voting Machines (EVMs), saying they were tamperproof and had passed all tests over the years.

"The EVM is tamperproof. That's the way they have been designed. The secret of their success lies in simplicity. They use calculator technology. It does not use an operating system. We don't use high technology here. Chances of going wrong is zero," Qureshi told reporters here.

Qureshi, on a two-day visit to the state along with Election Commissioner VS Sampath, was responding to questions about fears expressed by West Bengal's political parties about the machines.

Trinamool Congress chief and Railway Minister Mamata Banerjee had gone hammer and tongs against EVMs after her party was routed in the 2001 and 2006 assembly polls.

And after facing a drubbing in last year's Lok Sabha election, the state's ruling Left Front also doubted the genuineness of the machines.

Describing EVMs as the wonder machines of Indian democracy, Qureshi said: "They save 8,500 tonnes of papers in one general election."

"Firstly, these machines are manufactured by Bharat Heavy Electricals Ltd in Bangalore and the Electronic Corp of India Ltd in Hyderabad. These are two of the best companies. Nobody is allowed to enter (them) unauthorised.

"Where those machines will go nobody knows. How can they manipulate? How does one know which candidates will be contesting? And the names are given in the alphabetical order of the candidates. So it is not known button one will be this party and no 2 (for) that party," Qureshi said.

He said EVMs have passed all technical checks undertaken before political parties and candidates.

"They raised lot of doubts, but in the end said the machines are perfectly fine."

He said there were surprising results in Kolkata in the last election. "Those in power lost. So now they have questioned the machine."

Asked about the problem of the voting pattern of a booth becoming public due to the use of the EVMs, he said: "We have developed a machine called totalizer through which we can connect 14 machines, jumble up the votes of all the EVMs. The total number of the votes will be the sum-total of the votes in each EVM. It is like the votes getting mixed as in ballots.

"However, there were lot of reservations expressed. The matter is now before parliament," he added.